Open Fireplace vs Fireplace Insert Heating Cost Calculator

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Compare annual firewood and operating costs for an open fireplace and a wood insert that deliver the same room heat.

Advanced options
Yearly maintenance
Insert blower electricity
Estimated net annual operating savings with the insert
Estimated simple payback for the installed insert
Estimated annual firewood spending savedThis compares firewood spending before electricity and maintenance.
Estimated wood insert annual operating costIncludes insert firewood, blower electricity, and insert maintenance.
Estimated open fireplace annual operating costIncludes current firewood spending and entered fireplace maintenance.
Estimated wood insert use for equal room heatThis holds estimated delivered room heat equal. It does not promise whole-home heating.
Estimated wood insert firewood cost
Current open fireplace firewood cost
Estimated insert blower electricity cost
This estimate does not add a dollar value for extra central-heating demand caused by open-fireplace chimney draft. Weather, wood moisture, operation, and heat movement through the home can change actual costs.
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How to use our Open Fireplace vs Fireplace Insert Heating Cost Calculator

  1. Enter your Firewood price and Open fireplace wood use from delivery records, receipts, or your best seasonal estimate.
  2. Enter the Open fireplace overall efficiency as a planning assumption, then use the selected model's Wood insert overall efficiency from its manual or listing.
  3. Enter the Total installed insert cost from an all-in quote that includes the insert, liner or venting, labor, permits, electrical work, and repairs.
  4. Open Advanced options to add maintenance, blower power, blower use, and Electricity price if you want recurring costs included.
  5. Click Calculate, then check that Estimated wood insert use for equal room heat is believable for your expected use and read the signed savings result before relying on payback.
Example inputs for Open Fireplace vs Fireplace Insert Heating Cost Calculator
Example inputs for Open Fireplace vs Fireplace Insert Heating Cost Calculator

Definitions

Overall efficiency: The share of heat in the wood that reaches the living space. It is different from combustion efficiency; use the appliance's overall-efficiency value when available. [1]

Cord: A firewood volume unit used for pricing and seasonal use. Use the same cord basis for Firewood price and Open fireplace wood use.

Delivered room heat: Heat that reaches the room from the appliance. The comparison keeps this amount the same for both setups.

Blower electricity cost: The estimated cost to run an insert blower, based on its watts, yearly run time, and Electricity price.

Simple payback: Total installed insert cost divided by positive yearly operating savings. It estimates how many years savings take to equal the upfront cost.

Wood needed for equal room heatExample: 2 cords in an open fireplace at 15% efficiency versus an insert at 70% efficiency.. Higher insert efficiency can reduce wood needed for the same estimated delivered room heat.Wood needed for equal room heatExample: 2 cords in an open fireplace at 15% efficiency versus an insert at 70% efficiency.Open fireplace2 cords/yearWood insert0.43 cords/yearHeating setup
Wood needed for equal room heat
Higher insert efficiency can reduce wood needed for the same estimated delivered room heat.

Common mistakes and quick fixes

Mistake: Entering a full delivery total in Firewood price instead of a price for one cord.
Fix: Divide the delivery total by the number of cords, then enter the $ per cord amount.

Mistake: Using combustion efficiency for Wood insert overall efficiency.
Fix: Use the model's overall efficiency, which is the share of fuel heat delivered to the space.

Mistake: Leaving out a liner, permit, or labor from Total installed insert cost.
Fix: Enter the all-in project quote, not only the appliance price.

Mistake: Putting blower wattage into Blower use or entering cents as dollars in Electricity price.
Fix: Put the label rating in watts, annual run time in hours per year, and enter 17.3 cents per kWh as 0.173.

Mistake: Treating a negative Estimated net annual operating savings with the insert as a calculator error.
Fix: A negative value means the entered insert scenario costs more each year; revise the inputs or do not expect simple payback.

Limitations & Key Assumptions / Boundary Conditions

  • The calculation holds delivered room heat equal. It does not estimate a whole-home heating load or promise that either appliance will heat the entire home.
  • It assumes both setups use wood with the same heat per cord. Wood species, moisture, cord measurement, storage, and burn habits can change actual use.
  • Open fireplace overall efficiency is often an estimate. Fireplace design, doors, chimney draft, and operation can cause real performance to differ.
  • Chimney draft from an open fireplace can increase central-heating demand. This calculator does not assign an unsupported dollar amount to that effect.
  • Simple payback excludes financing, taxes, inflation, resale value, future fuel-price changes, and repair costs not entered as maintenance.
  • Use local codes and a qualified installer to assess fit, clearances, chimney condition, liner needs, and safety. Cost savings do not determine whether an installation is suitable.

Methodology

Equal room-heat comparison

The current open fireplace sets the target amount of delivered room heat. The calculator estimates how many cords the insert needs to provide that same heat, using the two entered overall-efficiency percentages.

annual_insert_cords = annual_open_cords * open_efficiency / insert_efficiency

For example, 2 cords per year at 15% open-fireplace efficiency and 70% insert efficiency gives 2 * 15 / 70 = 0.4286 cords per year for the insert estimate.

Annual operating costs

open_annual_fuel_cost = annual_open_cords * firewood_price

insert_annual_fuel_cost = annual_insert_cords * firewood_price

blower_electricity_cost = blower_power / 1000 * blower_hours * electricity_rate

The 1,000 conversion changes blower watts into kilowatts. Open fireplace annual operating cost adds Open fireplace maintenance to its fuel cost. Wood insert annual operating cost adds blower electricity and Wood insert maintenance to its fuel cost.

net_annual_savings = open_annual_operating_cost - insert_annual_operating_cost

A positive savings value means the insert has a lower estimated recurring yearly cost. A negative value is kept as negative and means the entered insert scenario costs more yearly.

Payback and calculation boundaries

simple_payback_years = total_installed_cost / net_annual_savings

Simple payback is calculated only when net annual savings are positive. If savings are zero or negative, the calculator states that payback is not reached under the entered assumptions. The method does not include financing, fuel-price changes, resale value, or a dollar estimate for added central-heating demand from fireplace draft.

Sources

  1. Energy Efficiency and Your Wood-Burning Appliance | US EPA